func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in ints {
        if i > 0 {
            sum += i
        }
    }
    return sum
}

func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in ints {
        if i < 0 {
            sum += i
        }
    }
    return sum
}

func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 2..<ints.count {
        sum += ints[i]
    }
    return sum
}

func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 0..<ints.count-2 {
        sum += ints[i]
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the positive integers.
// sum(ints: []) == 0
// sum(ints: [1, 2, 3, 4, 5]) == 15
// sum(ints: [-1, -2, -3, -4, -5]) == 0
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in ints {
        if i > 0 {
            sum += i
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the negative integers.
// sum(ints: []) == 0
// sum(ints: [1, 2, 3, 4, 5]) == 0
// sum(ints: [-1, -2, -3, -4, -5]) == -15
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in ints {
        if i < 0 {
            sum += i
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the first two.
// sum(ints: [1, 2, 3, 4, 5]) == 10
// sum(ints: [1, 2, 3, 4, 5, 6]) == 15
// sum(ints: [1, 2, 3, 4, 5, 6, 7]) == 21
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 2..<ints.count {
        sum += ints[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last two.
// sum(ints: [1, 2, 3, 4, 5]) == 9
// sum(ints: [1, 2, 3, 4, 5, 6]) == 15
// sum(ints: [1, 2, 3, 4, 5, 6, 7]) == 21
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 0..<ints.count-2 {
        sum += ints[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last two.
// sum(ints: [1, 2, 3, 4, 5]) == 9
// sum(ints: [1, 2, 3, 4, 5, 6]) == 15
// sum(ints: [1, 2, 3, 4, 5, 6, 7]) == 21
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 0..<ints.count-2 {
        sum += ints[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last two.
// sum(ints: [1, 2, 3, 4, 5]) == 9
// sum(ints: [1, 2, 3, 4, 5, 6]) == 15
// sum(ints: [1, 2, 3, 4, 5, 6, 7]) == 21
func sum(ints: [Int]) -> Int {
    var sum = 0
    for i in 0..<ints.count-2 {
        sum += ints[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last two.
// sum(ints: [1, 2, 3, 4, 5]) == 9
// sum(ints: [1, 2, 3, 4, 5, 6]) == 15
// sum(ints: [1, 2

func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func sum(ints: [Int]) -> Int {
  var sum = 0
  for i in ints {
    sum += i
  }
  return sum
}

func sum(ints: [Int]) -> Int {
  return ints.reduce(0, +)
}

func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  var sum = 0
  for i in ints {
    sum += i
  }
  return sum
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, +)
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {
  return ints.reduce(0, { $0 + $1 })
}

// Given an array of integers, return the sum of all the elements.
// sum(ints: []) == 0
// sum(ints: [42]) == 42
// sum(ints: [1, 2, 3]) == 6
func sum(ints: [Int]) -> Int {

func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func longest2(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func longest3(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func longest4(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func longest5(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func longest6(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest2(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest3(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest4(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest5(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest6(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest7(strings

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func first(string: String) -> Character? {
    if string.count == 0 {
        return nil
    }
    return string[string.startIndex]
}

func first(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[0]
}

func last(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[strings.count - 1]
}

func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[index]
}

func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 {
        return nil
    }
    return strings[index]
}

func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 || index >= strings.count {
        return nil
    }
    return strings[index]
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Given a string, return the first character. If the string is empty, return nil.
// first(string: "") == nil
// first(string: "abc") == "a"
func first(string: String) -> Character? {
    if string.count == 0 {
        return nil
    }
    return string[string.startIndex]
}

// Given an array of strings, return the first one. If the array is empty, return nil.
// first(strings: [] as [String]) == nil
// first(strings: ["a", "b", "c"]) == "a"
func first(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[0]
}

// Given an array of strings, return the last one. If the array is empty, return nil.
// last(strings: [] as [String]) == nil
// last(strings: ["a", "b", "c"]) == "c"
func last(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[strings.count - 1]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: [] as [String], index: 0) == nil
// get(strings: ["a", "b", "c"], index: 1) == "b"
func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    return strings[index]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: ["a", "b", "c"], index: -1) == nil
// get(strings: ["a", "b", "c"], index: 3) == nil
func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 {
        return nil
    }
    return strings[index]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: ["a", "b", "c"], index: 3) == nil
// get(strings: ["a", "b", "c"], index: 3) == nil
func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 || index >= strings.count {
        return nil
    }
    return strings[index]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: ["a", "b", "c"], index: 3) == nil
// get(strings: ["a", "b", "c"], index: 3) == nil
func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 || index >= strings.count {
        return nil
    }
    return strings[index]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: ["a", "b", "c"], index: 3) == nil
// get(strings: ["a", "b", "c"], index: 3) == nil
func get(strings: [String], index: Int) -> String? {
    if strings.count == 0 {
        return nil
    }
    if index < 0 || index >= strings.count {
        return nil
    }
    return strings[index]
}

// Given an array of strings, return the one at the given index. If the array is empty, return nil.
// get(strings: ["a", "b", "c"], index: 3) == nil
// get(strings: ["

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

// Given an array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

func sum_two_largest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[ints.count - 2] + ints[ints.count - 1]
}

func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[0] + ints[1]
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.isEmpty {
    return nil
  }
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

// Given an array of integers, return the sum of the two largest integers.
// sum_two_largest(ints: [1, 2, 3]) == 5
// sum_two_largest(ints: [1, 3, 4]) == 7
func sum_two_largest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[ints.count - 2] + ints[ints.count - 1]
}

// Given an array of integers, return the sum of the two smallest integers.
// sum_two_smallest(ints: [1, 2, 3]) == 3
// sum_two_smallest(ints: [1, 3, 4]) == 3
func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[0] + ints[1]
}

// Given an array of integers, return the sum of the two smallest integers.
// sum_two_smallest(ints: [1, 2, 3]) == 3
// sum_two_smallest(ints: [1, 3, 4]) == 3
func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[0] + ints[1]
}

// Given an array of integers, return the sum of the two largest integers.
// sum_two_largest(ints: [1, 2, 3]) == 5
// sum_two_largest(ints: [1, 3, 4]) == 7
func sum_two_largest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[ints.count - 2] + ints[ints.count - 1]
}

// Given an array of integers, return the sum of the two smallest integers.
// sum_two_smallest(ints: [1, 2, 3]) == 3
// sum_two_smallest(ints: [1, 3, 4]) == 3
func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[0] + ints[1]
}

// Given an array of integers, return the sum of the two largest integers.
// sum_two_largest(ints: [1, 2, 3]) == 5
// sum_two_largest(ints: [1, 3, 4]) == 7
func sum_two_largest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[ints.count - 2] + ints[ints.count - 1]
}

// Given an array of integers, return the sum of the two smallest integers.
// sum_two_smallest(ints: [1, 2, 3]) == 3
// sum_two_smallest(ints: [1, 3, 4]) == 3
func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[0] + ints[1]
}

// Given an array of integers, return the sum of the two largest integers.
// sum_two_largest(ints: [1, 2, 3]) == 5
// sum_two_largest(ints: [1, 3, 4]) == 7
func sum_two_largest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return ints[ints.count - 2] + ints[ints.count - 1]
}

// Given an array of integers, return the sum of the two smallest integers.
// sum_two_smallest(ints: [1, 2, 3]) == 3
// sum_two_smallest(ints: [1, 3, 4]) == 3
func sum_two_smallest(ints: [Int]) -> Int {
  var ints = ints
  ints.sort()
  return

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<bos><start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count > $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count > $1.count }
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count > $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count > $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count > $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count > $1.count })
}
```

func longest(strings: [String]) -> String? {
    // Your code goes here
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // Your code goes here
}
```

func longest(strings: [String]) -> String? {
    // TODO: implement
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: implement
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    // TODO: implement
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: implement
}
```

func longest(strings: [String]) -> String? {
    // TODO: implement
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: implement
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    // TODO: implement me
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: implement me
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    var maxLength = 0
    
    for string in strings {
        let length = string.count
        if length > maxLength {
            maxLength = length
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    var maxLength = 0
    
    for string in strings {
        let length = string.count
        if length > maxLength {
            maxLength = length
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString = strings.first
    var maxLength = longestString?.count?? 0

    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }

    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString = strings.first
    var maxLength = longestString?.count?? 0

    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings.first
    var maxLength = longestString?.count?? 0
    
    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings.first
    var maxLength = longestString?.count?? 0
    
    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    var maxLength = longestString.count
    
    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    var maxLength = longestString.count
    
    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard strings.count > 0 else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard strings.count > 0 else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    var result = [[Double]

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    for i in
    
    
        
    var maxLength

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    
    guard strings.forEach {
        
        

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    for i in

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    guard let result = [[Double](repeeksegments = [[Double]
    
    
    
    
    
    
    

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {
    
    
    
    
    

import Foundation

func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

```swift
import Foundation

/* 
 Function to multiply two matrices represented as 2D arrays of Doubles.
 Returns a new matrix that is the product of `lhs` and `rhs`, or `nil` if the matrices cannot be multiplied.
 */
func multiply(_ lhs: [[Double]], _ rhs: [[Double]]) -> [[Double]]? {
    guard lhs[0].count == rhs.count else { 
        return nil 
    }
    
    var result = [[Double]](repeating: [Double](repeating: 0, count: rhs[0].count), count: lhs.count)
    for i in 0..<lhs.count {
        for j in 0..<rhs[0].count {
            for k in 0..<rhs.count {
                result[i][j] += lhs[i][k] * rhs[k][j]
            }
        }
    }
    
    return result
}

/*
 Out of array of strings, return the longest one. Return the first one in case of multiple
 strings of the same length. Return nil in case the input array is empty.
 longest(strings: [] as [String]) == nil
 longest(strings: ["a", "b", "c"]) == "a"
 longest(strings: ["a", "bb", "ccc"]) == "ccc"
 */
func longest(strings: [String]) -> String? {

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty return nil
    return strings.max(by(strings.reduce(by { $0) { string in
        {

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    }

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    }
    }
    return strings.max(strings
    

func longest(strings: [String]) -> String? {
if strings.isEmpty returns the longest(strings: String? {
    return nil
    return nil
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
if strings.isEmpty returns the longest(strings: String? {
    return nil
    return nil
} else {
    return strings.max(

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    return nil
    }
    }
    return strings
    var longest =
    
    
    
    
    
    
    var longestString in
    guard let maxLength = strings.maxLength = strings.reduce(strings.max(strings.min(strings.minLen = strings.reduce(first
       .reduce(first?.count

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    return strings.max(strings.reduce(strings.min(by

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<｜begin▁of▁sentence｜>You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
import Foundation

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    var maxLength = 0
    
    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    var maxLength = 0
    
    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString: String? = nil
    var maxLength = 0
    
    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString: String? = nil
    var maxLength = 0
    
    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
  guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
  return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
  return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest2(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest3(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest4(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest5(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest6(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

func longest7(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest2(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest3(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest4(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest5(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest6(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest7(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest8(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
  guard let first = strings.first else { return nil }
  return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  guard let first = strings.first else { return nil }
  return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longestString = nil
    for string in strings {
        if longestString == nil || string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = nil
    for string in strings {
        if longestString == nil || string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Version

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    return strings.max { $0.count < $1.count }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    return strings.max { $0.count < $1.count }
}
```
### Version

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Version

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    return strings.sorted(by: { $0.count > $1.count }).first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```
### Ex

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    return strings.max { $0.count < $1.count }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    return strings.max { $0.count < $1.count }
}
```
### Ex

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.reduce(first) { $0.count > $1.count ? $0 : $1 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.reduce(first) { $0.count > $1.count ? $0 : $1 }
}
```
### Link

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    return strings.max()
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    return strings.max()
}
```
### Link

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```
### Link

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}
```
### Link

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.reduce(first) { $0.count > $1.count ? $0 : $1 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else { return nil }
    return strings.reduce(first) { $0.count > $1.count ? $0 : $1 }
}
```
### Link

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else {
        return nil
    }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard let maxString = strings.max(by: { $0.count < $1.count }) else { return nil }
    return maxString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let maxString = strings.max(by: { $0.count < $1.count }) else { return nil }
    return maxString
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: { $0.count < $1.count }) else { return nil }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: {$0.count < $1.count}) else { return nil }
    return max
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let max = strings.max(by: {$0.count < $1.count}) else { return nil }
    return max
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.reduce(nil) { (longestString: String?, currentString: String) -> String? in
        return longestString?.count ?? 0 < currentString.count ? currentString : longestString
    }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.reduce(nil) { (longestString: String?, currentString: String) -> String? in
        return longestString?.count ?? 0 < currentString.count ? currentString : longestString
    }
}

// Example usage:
print(longest(strings: [])) // Output: nil
print(longest(strings: ["A", "b", "c"])) // Output: "A"
print(longest(strings: ["A", "bb", "ccc"])) // Output: "ccc"
```

This function uses the `reduce` method to iterate over the array of strings and keep track of the longest string seen so far. If the current string is longer than the longest string seen so far, it becomes the new longest string. If the array is empty, the function returns `nil`.

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.reduce(nil) { (longestString: String?, currentString: String) -> String? in
        return longestString?.count ?? 0 < currentString.count ? currentString : longestString
    }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.reduce(nil) { (longestString: String?, currentString: String) -> String? in
        return longestString?.count ?? 0 < currentString.count ? currentString : longestString
    }
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

// Example usage:
print(longest(strings: ["hello", "world", "python", "programming"]))  // Output: "programming"
print(longest(strings: ["short", "longer", "longest"]))                // Output: "longest"
print(longest(strings: []))                                            // Output: nil
```

This function iterates through the array of strings and keeps track of the longest string seen so far. If there are multiple strings with the same maximum length, the first one encountered is returned. If the input array is empty, the function returns nil.

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

// Example usage:
print(longest(strings: ["hello", "world", "python", "programming"])) // Output: "programming"
print(longest(strings: ["short", "longer", "longest"]))               // Output: "longest"
print(longest(strings: []))                                           // Output: nil
```

This function iterates through the array of strings and keeps track of the longest string seen so far. If there are multiple strings with the same maximum length, the first one encountered is returned. If the input array is empty, the function returns nil.

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

// Example usage:
print(longest(strings: ["hello", "world", "python", "programming"])) // Output: "programming"
print(longest(strings: ["short", "longer", "longest"]))              // Output: "longest"
print(longest(strings: []))                                           // Output: nil
```

This function iterates through the array of strings and keeps track of the longest one seen so far. If there are multiple strings with the same maximum length, it returns the first one encountered. If the input array is empty, it returns nil.

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func shortest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var shortest = strings[0]
    for string in strings {
        if string.count < shortest.count {
            shortest = string
        }
    }
    
    return shortest
}

func longestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

func shortestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var shortest = strings[0]
    for string in strings {
        if string.count < shortest.count {
            shortest = string
        }
    }
    
    return shortest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the shortest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// shortest(strings: [] as [String]) == nil
// shortest(strings: ["a", "b", "c"]) == "a"
// shortest(strings: ["a", "bb", "ccc"]) == "a"
func shortest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var shortest = strings[0]
    for string in strings {
        if string.count < shortest.count {
            shortest = string
        }
    }
    
    return shortest
}

// Out of array of strings, return the one with the longest length. Return the first one in case of
// multiple strings of the same length. Return nil in case the input array is empty.
// longest_by_length(strings: [] as [String]) == nil
// longest_by_length(strings: ["a", "b", "c"]) == "c"
// longest_by_length(strings: ["a", "bb", "ccc"]) == "ccc"
func longestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the one with the shortest length. Return the first one in case of
// multiple strings of the same length. Return nil in case the input array is empty.
// shortest_by_length(strings: [] as [String]) == nil
// shortest_by_length(strings: ["a", "b", "c"]) == "a"
// shortest_by_length(strings: ["a", "bb", "ccc"]) == "a"
func shortestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var shortest = strings[0]
    for string in strings {
        if string.count < shortest.count {
            shortest = string
        }
    }
    
    return shortest
}

// Out of array of strings, return the one with the longest length. Return the first one in case of
// multiple strings of the same length. Return nil in case the input array is empty.
// longest_by_length(strings: [] as [String]) == nil
// longest_by_length(strings: ["a", "b", "c"]) == "c"
// longest_by_length(strings: ["a", "bb", "ccc"]) == "ccc"
func longestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

// Out of array of strings, return the one with the shortest length. Return the first one in case of
// multiple strings of the same length. Return nil in case the input array is empty.
// shortest_by_length(strings: [] as [String]) == nil
// shortest_by_length(strings: ["a", "b", "c"]) == "a"
// shortest_by_length(strings: ["a", "bb", "ccc"]) == "a"
func shortestByLength(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var shortest = strings[0]
    for string in strings {
        if string.count < shortest.count {
            shortest = string
        }
    }
    
    return shortest
}

// Out of array of strings, return the one with the longest length. Return the first one in case of
// multiple strings of the same length. Return nil in case the input array is empty.
// longest_by_length(strings: [] as [String]) == nil
// longest_by_length(strings:

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

func sumEven(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 == 0 {
            sum += integers[i]
        }
    }
    return sum
}

func sumOdd(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 != 0 {
            sum += integers[i]
        }
    }
    return sum
}

func sumModulo3(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 3
    }
    return sum
}

func sumModulo5(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 5
    }
    return sum
}

func sumModulo7(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 7
    }
    return sum
}

func sumModulo11(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 11
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the integers.
// sum(integers: []) == 0
// sum(integers: [1, 2, 3]) == 6
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the even integers.
// sumEven(integers: []) == 0
// sumEven(integers: [1, 2, 3]) == 2
// sumEven(integers: [1, 2, 3, 4]) == 6
func sumEven(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 == 0 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the odd integers.
// sumOdd(integers: []) == 0
// sumOdd(integers: [1, 2, 3]) == 0
// sumOdd(integers: [1, 2, 3, 4]) == 4
func sumOdd(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 != 0 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers modulo 3.
// sumModulo3(integers: []) == 0
// sumModulo3(integers: [1, 2, 3]) == 1
// sumModulo3(integers: [1, 2, 3, 4]) == 2
func sumModulo3(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 3
    }
    return sum
}

// Given an array of integers, return the sum of all the integers modulo 5.
// sumModulo5(integers: []) == 0
// sumModulo5(integers: [1, 2, 3]) == 1
// sumModulo5(integers: [1, 2, 3, 4]) == 0
func sumModulo5(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 5
    }
    return sum
}

// Given an array of integers, return the sum of all the integers modulo 7.
// sumModulo7(integers: []) == 0
// sumModulo7(integers: [1, 2, 3]) == 2
// sumModulo7(integers: [1, 2, 3, 4]) == 3
func sumModulo7(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 7
    }
    return sum
}

// Given an array of integers, return the sum of all the integers modulo 11.
// sumModulo11(integers: []) == 0
// sumModulo11(integers: [1, 2, 3]) == 2
// sumModulo11(integers: [1, 2, 3, 4]) == 4
func sumModulo11(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i] % 11
    }
    return sum
}

// Given an array of integers, return the sum of all the integers modulo 13.
// sumModulo13(integers: []) == 0
// sumModulo13(integers: [1, 2, 3]) == 3
// sumModulo13(integers: [1, 2, 3, 4]) == 

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

func sumEven(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 == 0 {
            sum += integers[i]
        }
    }
    return sum
}

func sumOdd(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 != 0 {
            sum += integers[i]
        }
    }
    return sum
}

func sumAllButFirst(integers: [Int]) -> Int {
    var sum = 0
    for i in 1..<integers.count {
        sum += integers[i]
    }
    return sum
}

func sumAllButLast(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count-1 {
        sum += integers[i]
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the integers. Return 0 in case the input array is empty.
// sum(integers: [] as [Int]) == 0
// sum(integers: [1, 2, 3]) == 6
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the even integers. Return 0 in case the input array is empty.
// sumEven(integers: [] as [Int]) == 0
// sumEven(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 30
func sumEven(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 == 0 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the odd integers. Return 0 in case the input array is empty.
// sumOdd(integers: [] as [Int]) == 0
// sumOdd(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 25
func sumOdd(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if integers[i] % 2 != 0 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the first one. Return 0 in case the input array is empty.
// sumAllButFirst(integers: [] as [Int]) == 0
// sumAllButFirst(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sumAllButFirst(integers: [Int]) -> Int {
    var sum = 0
    for i in 1..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one. Return 0 in case the input array is empty.
// sumAllButLast(integers: [] as [Int]) == 0
// sumAllButLast(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sumAllButLast(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count-1 {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one. Return 0 in case the input array is empty.
// sumAllButLast(integers: [] as [Int]) == 0
// sumAllButLast(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sumAllButLast(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count-1 {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one. Return 0 in case the input array is empty.
// sumAllButLast(integers: [] as [Int]) == 0
// sumAllButLast(integers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == 55
func sumAllButLast(integers: [Int]) -> Int {

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func productExceptSelf(nums: [Int]) -> [Int] {
    var result = [Int](repeating: 1, count: nums.count)
    var left = 1
    for i in 0..<nums.count {
        result[i] = left
        left *= nums[i]
    }
    var right = 1
    for i in (0..<nums.count).reversed() {
        result[i] *= right
        right *= nums[i]
    }
    return result
}

func swapEnds(str: String) -> String {
    if str.count == 2 {
        return str
    }
    return String(str[str.index(str.startIndex, offsetBy: 1)]) + String(str[str.index(str.endIndex, offsetBy: -2)]) + String(str[str.index(str.startIndex, offsetBy: 1)])
}

func stringBits(str: String) -> String {
    var result = ""
    for i in 0..<str.count {
        if i % 2 == 0 {
            result += String(str[str.index(str.startIndex, offsetBy: i)])
        }
    }
    return result
}

func last2(str: String) -> Int {
    if str.count < 2 {
        return 0
    }
    var count = 0
    var last2 = str[str.index(str.endIndex, offsetBy: -2)..<str.endIndex]
    for i in 0..<str.count - 2 {
        if str[str.index(str.startIndex, offsetBy: i)] == str[str.index(str.startIndex, offsetBy: i + 1)] {
            if String(str[str.index(str.startIndex, offsetBy: i)]) + String(str[str.index(str.startIndex, offsetBy: i + 1)]) == last2 {
                count += 1
            }
        }
    }
    return count
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return an array of the same length, where each element is the product of all the elements in the original array except for the one at that index.
// productExceptSelf(nums: [1, 2, 3, 4]) == [24, 12, 8, 6]
// productExceptSelf(nums: [1, 2, 3, 0]) == [0, 0, 6, 0]
// productExceptSelf(nums: [1, 2, 3, 4, 5]) == [120, 60, 40, 30, 24]
func productExceptSelf(nums: [Int]) -> [Int] {
    var result = [Int](repeating: 1, count: nums.count)
    var left = 1
    for i in 0..<nums.count {
        result[i] = left
        left *= nums[i]
    }
    var right = 1
    for i in (0..<nums.count).reversed() {
        result[i] *= right
        right *= nums[i]
    }
    return result
}

// Given a string, return a new string with the first and last chars swapped, except keep the first and last chars if they appear at the beginning or end of the string. You may assume that the string has at least two chars.
// swapEnds("Hello") == "oellH"
// swapEnds("ab") == "ba"
// swapEnds("Hi") == "Hi"
func swapEnds(str: String) -> String {
    if str.count == 2 {
        return str
    }
    return String(str[str.index(str.startIndex, offsetBy: 1)]) + String(str[str.index(str.endIndex, offsetBy: -2)]) + String(str[str.index(str.startIndex, offsetBy: 1)])
}

// Given a string, return a new string made of every other char starting with the first, so "Hello" yields "Hlo".
// stringBits("Hello") == "Hlo"
// stringBits("Hi") == "H"
// stringBits("Heeololeo") == "Hello"
func stringBits(str: String) -> String {
    var result = ""
    for i in 0..<str.count {
        if i % 2 == 0 {
            result += String(str[str.index(str.startIndex, offsetBy: i)])
        }
    }
    return result
}

// Given a string, return the count of the number of times that a substring length 2 appears in the string and also as the last 2 chars of the string, so "hixxxhi" yields 1 (we won't count the end substring).
// last2("hixxhi") == 1
// last2("xaxxaxaxx") == 1
// last2("axxxaaxx") == 2
func last2(str: String) -> Int {
    if str.count < 2 {
        return 0
    }
    var count = 0
    var last2 = str[str.index(str.endIndex, offsetBy: -2)..<str.endIndex]
    for i in 0..<str.count - 2 {
        if str[str.index(str.startIndex, offsetBy: i)] == str[str.index(str.startIndex, offsetBy: i + 1)] {
            if String(str[str.index(str.startIndex, offsetBy: i)]) + String(str[str.index(str.startIndex, offsetBy: i + 1)]) == last2 {
                count += 1
            }
        }
    }
    return count
}

// Given an array of ints, return the number of times that two 6's are next to each other in the array. Also count instances where the second "6" is actually a 7.
// sixes9([6, 6, 2]) == 1
// sixes9([6, 6, 2, 6]) == 1
// sixes9([6, 7, 

func longest(strings: [String]) -> String? {
  if strings.count == 0 {
    return nil
  }
  
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
  if strings.count == 0 {
    return nil
  }
  
  var longest = strings[0]
  for i in 1..<strings.count {
    if strings[i].count > longest.count {
      longest = strings[i]
    }
  }
  return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 1..<integers.count {
        sum += integers[i]
    }
    return sum
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count - 1 {
        sum += integers[i]
    }
    return sum
}

func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if i != integers.count - 1 {
            sum += integers[i]
        }
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the integers.
// sum(integers: []) == 0
// sum(integers: [1, 2, 3]) == 6
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the first one.
// sum(integers: [1, 2, 3]) == 4
// sum(integers: [1, 2, 3, 4]) == 9
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 1..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one.
// sum(integers: [1, 2, 3]) == 4
// sum(integers: [1, 2, 3, 4]) == 8
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count - 1 {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one.
// sum(integers: [1, 2, 3, 4]) == 8
// sum(integers: [1, 2, 3, 4, 5]) == 14
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if i != integers.count - 1 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the first one.
// sum(integers: [1, 2, 3, 4]) == 8
// sum(integers: [1, 2, 3, 4, 5]) == 14
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 1..<integers.count {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one.
// sum(integers: [1, 2, 3, 4]) == 8
// sum(integers: [1, 2, 3, 4, 5]) == 14
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count - 1 {
        sum += integers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one.
// sum(integers: [1, 2, 3, 4]) == 8
// sum(integers: [1, 2, 3, 4, 5]) == 14
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if i != integers.count - 1 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last one.
// sum(integers: [1, 2, 3, 4]) == 8
// sum(integers: [1, 2, 3, 4, 5]) == 14
func sum(integers: [Int]) -> Int {
    var sum = 0
    for i in 0..<integers.count {
        if i != integers.count - 1 {
            sum += integers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the integers except for the last

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func largestSum(numbers: [Int]) -> Int {
    var largest = 0
    var secondLargest = 0
    for number in numbers {
        if number > largest {
            secondLargest = largest
            largest = number
        } else if number > secondLargest {
            secondLargest = number
        }
    }
    return largest + secondLargest
}

func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Given an array of integers, return the sum of the two largest numbers.
// largestSum([1, 2, 3, 4, 5]) == 10
// largestSum([1, 1, 1, 1]) == 2
func largestSum(numbers: [Int]) -> Int {
    var largest = 0
    var secondLargest = 0
    for number in numbers {
        if number > largest {
            secondLargest = largest
            largest = number
        } else if number > secondLargest {
            secondLargest = number
        }
    }
    return largest + secondLargest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max
    var secondSmallest = Int.max
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two smallest numbers.
// smallestSum([1, 2, 3, 4, 5]) == 3
// smallestSum([5, 5, 5, 5, 5]) == 10
func smallestSum(numbers: [Int]) -> Int {
    var smallest = Int.max

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

func sumLargest(numbers: [Int]) -> Int {
    var largest = numbers[0]
    var secondLargest = numbers[1]
    if secondLargest > largest {
        largest = secondLargest
        secondLargest = numbers[0]
    }
    for number in numbers {
        if number > largest {
            secondLargest = largest
            largest = number
        } else if number > secondLargest {
            secondLargest = number
        }
    }
    return largest + secondLargest
}

func sumSmallest(numbers: [Int]) -> Int {
    var smallest = numbers[0]
    var secondSmallest = numbers[1]
    if secondSmallest < smallest {
        smallest = secondSmallest
        secondSmallest = numbers[0]
    }
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

func sumLargestEven(numbers: [Int]) -> Int {
    var largest = numbers[0]
    var secondLargest = numbers[1]
    if secondLargest % 2 == 0 {
        largest = secondLargest
        secondLargest = numbers[0]
    }
    for number in numbers {
        if number % 2 == 0 {
            if number > largest {
                secondLargest = largest
                largest = number
            } else if number > secondLargest {
                secondLargest = number
            }
        }
    }
    return largest + secondLargest
}

func sumSmallestOdd(numbers: [Int]) -> Int {
    var smallest = numbers[0]
    var secondSmallest = numbers[1]
    if secondSmallest % 2 == 0 {
        smallest = secondSmallest
        secondSmallest = numbers[0]
    }
    for number in numbers {
        if number % 2 == 1 {
            if number < smallest {
                secondSmallest = smallest
                smallest = number
            } else if number < secondSmallest {
                secondSmallest = number
            }
        }
    }
    return smallest + secondSmallest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

// Given an array of integers, return the sum of the two largest numbers.
// sumLargest(numbers: [1, 2, 3]) == 5
// sumLargest(numbers: [1, 2, 3, 4, 5]) == 10
// sumLargest(numbers: [1, 3, 4, 2, 5]) == 10
func sumLargest(numbers: [Int]) -> Int {
    var largest = numbers[0]
    var secondLargest = numbers[1]
    if secondLargest > largest {
        largest = secondLargest
        secondLargest = numbers[0]
    }
    for number in numbers {
        if number > largest {
            secondLargest = largest
            largest = number
        } else if number > secondLargest {
            secondLargest = number
        }
    }
    return largest + secondLargest
}

// Given an array of integers, return the sum of the two smallest numbers.
// sumSmallest(numbers: [1, 2, 3]) == 3
// sumSmallest(numbers: [1, 2, 3, 4, 5]) == 6
// sumSmallest(numbers: [1, 3, 4, 2, 5]) == 3
func sumSmallest(numbers: [Int]) -> Int {
    var smallest = numbers[0]
    var secondSmallest = numbers[1]
    if secondSmallest < smallest {
        smallest = secondSmallest
        secondSmallest = numbers[0]
    }
    for number in numbers {
        if number < smallest {
            secondSmallest = smallest
            smallest = number
        } else if number < secondSmallest {
            secondSmallest = number
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two largest even numbers.
// sumLargestEven(numbers: [1, 2, 3]) == 2
// sumLargestEven(numbers: [1, 2, 3, 4, 5]) == 6
// sumLargestEven(numbers: [1, 3, 4, 2, 5]) == 6
func sumLargestEven(numbers: [Int]) -> Int {
    var largest = numbers[0]
    var secondLargest = numbers[1]
    if secondLargest % 2 == 0 {
        largest = secondLargest
        secondLargest = numbers[0]
    }
    for number in numbers {
        if number % 2 == 0 {
            if number > largest {
                secondLargest = largest
                largest = number
            } else if number > secondLargest {
                secondLargest = number
            }
        }
    }
    return largest + secondLargest
}

// Given an array of integers, return the sum of the two smallest odd numbers.
// sumSmallestOdd(numbers: [1, 2, 3]) == 3
// sumSmallestOdd(numbers: [1, 2, 3, 4, 5]) == 6
// sumSmallestOdd(numbers: [1, 3, 4, 2, 5]) == 6
func sumSmallestOdd(numbers: [Int]) -> Int {
    var smallest = numbers[0]
    var secondSmallest = numbers[1]
    if secondSmallest % 2 == 0 {
        smallest = secondSmallest
        secondSmallest = numbers[0]
    }
    for number in numbers {
        if number % 2 == 1 {
            if number < smallest {
                secondSmallest = smallest
                smallest = number
            } else if number < secondSmallest {
                secondSmallest = number
            }
        }
    }
    return smallest + secondSmallest
}

// Given an array of integers, return the sum of the two largest odd numbers.
// sumLargestOdd(numbers: [1, 2, 3]) == 2
// sumLargestOdd(numbers: [1, 2, 3, 4, 5]) == 6
// sumLargestOdd(numbers: [1, 3, 4, 2, 5]) == 6
func sumLargestOdd(numbers: [Int]) -> Int {
    var largest = numbers[0]
    var secondLargest

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}
<|file_separator|>```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sumOfEvens(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 == 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfOdds(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 != 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfPositives(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] > 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfNegatives(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] < 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfAll(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

func sumOfRest(numbers: [Int]) -> Int {
    var sum = 0
    for i in 1..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

func sumOfButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count-1 {
        sum += numbers[i]
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the even numbers.
// sumOfEvens([2, 1, 2, 3, 4]) == 6
// sumOfEvens([2, 5, 6, 3, 4]) == 12
func sumOfEvens(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 == 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the odd numbers.
// sumOfOdds([2, 1, 2, 3, 4]) == 4
// sumOfOdds([2, 5, 6, 3, 4]) == 5
func sumOfOdds(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 != 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the positive numbers.
// sumOfPositives([2, 1, 2, 3, 4]) == 10
// sumOfPositives([2, -1, 2, 3, 4]) == 10
func sumOfPositives(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] > 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the negative numbers.
// sumOfNegatives([2, 1, 2, 3, 4]) == 0
// sumOfNegatives([2, -1, 2, 3, 4]) == 6
func sumOfNegatives(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] < 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers.
// sumOfAll([2, 1, 2, 3, 4]) == 10
// sumOfAll([2, -1, 2, 3, 4]) == 10
func sumOfAll(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except the first one.
// sumOfRest([2, 1, 2, 3, 4]) == 10
// sumOfRest([2, -1, 2, 3, 4]) == 10
func sumOfRest(numbers: [Int]) -> Int {
    var sum = 0
    for i in 1..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except the last one.
// sumOfButLast([2, 1, 2, 3, 4]) == 9
// sumOfButLast([2, -1, 2, 3, 4]) == 9
func sumOfButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count-1 {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except the last one.
// sumOfButLast([2, 1, 2, 3, 4]) == 9
// sumOfButLast([2, -1, 2, 3, 4]) == 9
func sumOfButLast(numbers: [Int])

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

func sumOfEvens(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 == 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfOdds(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 != 0 {
            sum += numbers[i]
        }
    }
    return sum
}

func sumOfAll(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

func sumOfAllButFirst(numbers: [Int]) -> Int {
    var sum = 0
    for i in 1..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

func sumOfAllButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count - 1 {
        sum += numbers[i]
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longest = strings[0]
    for i in 1..<strings.count {
        if strings[i].count > longest.count {
            longest = strings[i]
        }
    }
    return longest
}

// Given an array of integers, return the sum of all the even numbers.
// sumOfEvens([2, 1, 2, 3, 4]) == 6
// sumOfEvens([3, 4, 5, 6, 7, 8]) == 12
func sumOfEvens(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 == 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the odd numbers.
// sumOfOdds([2, 1, 2, 3, 4]) == 4
// sumOfOdds([3, 4, 5, 6, 7, 8]) == 16
func sumOfOdds(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        if numbers[i] % 2 != 0 {
            sum += numbers[i]
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers.
// sumOfAll([2, 1, 2, 3, 4]) == 10
// sumOfAll([3, 4, 5, 6, 7, 8]) == 36
func sumOfAll(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except for the first one.
// sumOfAllButFirst([2, 1, 2, 3, 4]) == 10
// sumOfAllButFirst([3, 4, 5, 6, 7, 8]) == 24
func sumOfAllButFirst(numbers: [Int]) -> Int {
    var sum = 0
    for i in 1..<numbers.count {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except for the last one.
// sumOfAllButLast([2, 1, 2, 3, 4]) == 9
// sumOfAllButLast([3, 4, 5, 6, 7, 8]) == 20
func sumOfAllButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count - 1 {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except for the last one.
// sumOfAllButLast([2, 1, 2, 3, 4]) == 9
// sumOfAllButLast([3, 4, 5, 6, 7, 8]) == 20
func sumOfAllButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count - 1 {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except for the last one.
// sumOfAllButLast([2, 1, 2, 3, 4]) == 9
// sumOfAllButLast([3, 4, 5, 6, 7, 8]) == 20
func sumOfAllButLast(numbers: [Int]) -> Int {
    var sum = 0
    for i in 0..<numbers.count - 1 {
        sum += numbers[i]
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers except for the last one.
// sumOfAllButLast([2, 1, 2, 3, 4]) == 9

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    return strings.sorted { $0.count > $1.count }.first
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var max = strings[0]
    for string in strings {
        if string.count > max.count {
            max = string
        }
    }
    return max
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var max = strings[0]
    for string in strings {
        if string.count > max.count {
            max = string
        }
    }
    return max
}
```

func longest(strings: [String]) -> String? {
    guard strings.count > 0 else {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard strings.count > 0 else {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength: Int = 0
    for _, string in strings {
        if string.length > longestStringLength {
            longestString = string
            longestStringLength = string.length
        }
    }
    return longestString
}

func longer_strings(strings: [String], n: Int) -> [String] {
    var longerStrings: [String] = []
    for _, string in strings {
        if string.length > n {
            longerStrings.append(string)
        }
    }
    return longerStrings
}

func shorter_strings(strings: [String], n: Int) -> [String] {
    var shorterStrings: [String] = []
    for _, string in strings {
        if string.length < n {
            shorterStrings.append(string)
        }
    }
    return shorterStrings
}

func starts_with_a(strings: [String]) -> [String] {
    var startsWithA: [String] = []
    for _, string in strings {
        if string.subscript(0) == "a" {
            startsWithA.append(string)
        }
    }
    return startsWithA
}

func ends_with_a(strings: [String]) -> [String] {
    var endsWithA: [String] = []
    for _, string in strings {
        if string.subscript(string.length - 1) == "a" {
            endsWithA.append(string)
        }
    }
    return endsWithA
}

func contains_a(strings: [String]) -> [String] {
    var containsA: [String] = []
    for _, string in strings {
        if string.contains("a") {
            containsA.append(string)
        }
    }
    return containsA
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength: Int = 0
    for _, string in strings {
        if string.length > longestStringLength {
            longestString = string
            longestStringLength = string.length
        }
    }
    return longestString
}

// Given an array of strings, return a new array that contains only strings longer than n.
// longer_strings(strings: ["a", "b", "c"], n: 1) == ["b", "c"]
// longer_strings(strings: ["a", "b", "c"], n: 2) == ["a", "b", "c"]
// longer_strings(strings: ["a", "b", "c"], n: 3) == []
func longer_strings(strings: [String], n: Int) -> [String] {
    var longerStrings: [String] = []
    for _, string in strings {
        if string.length > n {
            longerStrings.append(string)
        }
    }
    return longerStrings
}

// Given an array of strings, return a new array that contains only strings shorter than n.
// shorter_strings(strings: ["a", "b", "c"], n: 1) == ["a"]
// shorter_strings(strings: ["a", "b", "c"], n: 2) == ["b"]
// shorter_strings(strings: ["a", "b", "c"], n: 3) == ["a", "b", "c"]
func shorter_strings(strings: [String], n: Int) -> [String] {
    var shorterStrings: [String] = []
    for _, string in strings {
        if string.length < n {
            shorterStrings.append(string)
        }
    }
    return shorterStrings
}

// Given an array of strings, return a new array that contains only strings that start with
// the letter a.
// starts_with_a(strings: ["a", "b", "c"]) == ["a"]
// starts_with_a(strings: ["a", "b", "c"]) == ["a"]
// starts_with_a(strings: ["a", "b", "c"]) == ["a"]
func starts_with_a(strings: [String]) -> [String] {
    var startsWithA: [String] = []
    for _, string in strings {
        if string.subscript(0) == "a" {
            startsWithA.append(string)
        }
    }
    return startsWithA
}

// Given an array of strings, return a new array that contains only strings that end with the
// letter a.
// ends_with_a(strings: ["a", "b", "c"]) == []
// ends_with_a(strings: ["a", "b", "c"]) == []
// ends_with_a(strings: ["a", "b", "c"]) == []
func ends_with_a(strings: [String]) -> [String] {
    var endsWithA: [String] = []
    for _, string in strings {
        if string.subscript(string.length - 1) == "a" {
            endsWithA.append(string)
        }
    }
    return endsWithA
}

// Given an array of strings, return a new array that contains only strings that contain the
// letter a.
// contains_a(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// contains_a(strings: ["a", "b", "c"]) == ["a", "b", "c"]
// contains_a(strings: ["a", "b", "c"]) == ["a", "b", "c"]
func contains_a(strings: [String]) -> [String] {
    var containsA: [String] = []
    for _, string in strings {
        if string.contains("a") {
            containsA.append(string)
        }
    }
    return containsA
}

// Given an array of strings, return a new array that contains only strings that do not contain
// the letter a.
// does_not_contain_a(strings: ["a", "b", "c"]) == []
// does_not_contain_a(strings: ["a", "b", "c"]) == []
// does_not_contain_a(strings: ["a", "b", "c"]) == []
func does

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength:

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.count > longestString.count {
            longestString = s
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.count > longestString.count {
            longestString = s
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings

func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
        }
    }
    return longestString
}

func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
        }
    }
    return longestString
}

// Given an array of strings, return a new array with the longest string.
// longestString(strings: [] as [String]) == []
// longestString(strings: ["a", "b", "c"]) == ["c"]
// longestString(strings: ["a", "bb", "ccc"]) == ["ccc"]
func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

// Given an array of strings, return a new array with the longest string.
// longestString(strings: [] as [String]) == []
// longestString(strings: ["a", "b", "c"]) == ["c"]
// longestString(strings: ["a", "bb", "ccc"]) == ["ccc"]
func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

// Given an array of strings, return a new array with the longest string.
// longestString(strings: [] as [String]) == []
// longestString(strings: ["a", "b", "c"]) == ["c"]
// longestString(strings: ["a", "bb", "ccc"]) == ["ccc"]
func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

// Given an array of strings, return a new array with the longest string.
// longestString(strings: [] as [String]) == []
// longestString(strings: ["a", "b", "c"]) == ["c"]
// longestString(strings: ["a", "bb", "ccc"]) == ["ccc"]
func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

// Given an array of strings, return a new array with the longest string.
// longestString(strings: [] as [String]) == []
// longestString(strings: ["a", "b", "c"]) == ["c"]
// longestString(strings: ["a", "bb", "ccc"]) == ["ccc"]
func longestString(strings: [String]) -> [String] {
    if strings.isEmpty() {
        return []
    }
    var longestString = strings[0]
    var longestStrings = [String]()
    for _, string in strings {
        if string.length > longestString.length {
            longestString = string
            longestStrings = [string]()
        } else if string.length == longestString.length {
            longestStrings.append(string)
        }
    }
    return longestStrings
}

// Given an array of strings, return a

func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

func firstNonRepeatingCharacter(string: String) -> String? {
    var counts = [String: Int]()
    for _, c in string {
        counts[String(c)] = counts[String(c)] + 1
    }
    for _, c in string {
        if counts[String(c)] == 1 {
            return String(c)
        }
    }
    return nil
}

func firstRepeatingCharacter(string: String) -> String? {
    var counts = [String: Int]()
    for _, c in string {
        counts[String(c)] = counts[String(c)] + 1
    }
    for _, c in string {
        if counts[String(c)] > 1 {
            return String(c)
        }
    }
    return nil
}

func sumOfEvenNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        if n % 2 == 0 {
            sum += n
        }
    }
    return sum
}

func sumOfOddNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        if n % 2 == 1 {
            sum += n
        }
    }
    return sum
}

func sumOfNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        sum += n
    }
    return sum
}

func sumOfSquaredNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        sum += n * n
    }
    return sum
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty() {
        return nil
    }
    var longestString = strings[0]
    for _, s in strings {
        if s.length > longestString.length {
            longestString = s
        }
    }
    return longestString
}

// Given a string, return the first non-repeating character. Return nil in case of multiple
// non-repeating characters. Return nil in case the input string is empty.
// firstNonRepeatingCharacter(string: "") == nil
// firstNonRepeatingCharacter(string: "a") == "a"
// firstNonRepeatingCharacter(string: "abac") == "c"
func firstNonRepeatingCharacter(string: String) -> String? {
    var counts = [String: Int]()
    for _, c in string {
        counts[String(c)] = counts[String(c)] + 1
    }
    for _, c in string {
        if counts[String(c)] == 1 {
            return String(c)
        }
    }
    return nil
}

// Given a string, return the first repeating character. Return nil in case of multiple
// non-repeating characters. Return nil in case the input string is empty.
// firstRepeatingCharacter(string: "") == nil
// firstRepeatingCharacter(string: "a") == nil
// firstRepeatingCharacter(string: "abac") == "a"
// firstRepeatingCharacter(string: "abcab") == "b"
func firstRepeatingCharacter(string: String) -> String? {
    var counts = [String: Int]()
    for _, c in string {
        counts[String(c)] = counts[String(c)] + 1
    }
    for _, c in string {
        if counts[String(c)] > 1 {
            return String(c)
        }
    }
    return nil
}

// Given an array of integers, return the sum of all the even numbers. Return 0 in case of
// empty array.
// sumOfEvenNumbers(numbers: [] as [Int]) == 0
// sumOfEvenNumbers(numbers: [1, 2, 3, 4, 5]) == 6
// sumOfEvenNumbers(numbers: [1, 3, 5]) == 0
func sumOfEvenNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        if n % 2 == 0 {
            sum += n
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the odd numbers. Return 0 in case of
// empty array.
// sumOfOddNumbers(numbers: [] as [Int]) == 0
// sumOfOddNumbers(numbers: [1, 2, 3, 4, 5]) == 9
// sumOfOddNumbers(numbers: [1, 3, 5]) == 9
func sumOfOddNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        if n % 2 == 1 {
            sum += n
        }
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers. Return 0 in case of empty
// array.
// sumOfNumbers(numbers: [] as [Int]) == 0
// sumOfNumbers(numbers: [1, 2, 3, 4, 5]) == 15
// sumOfNumbers(numbers: [1, -2, 3, -4, 5]) == 9
func sumOfNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        sum += n
    }
    return sum
}

// Given an array of integers, return the sum of all the numbers squared. Return 0 in case of
// empty array.
// sumOfSquaredNumbers(numbers: [] as [Int]) == 0
// sumOfSquaredNumbers(numbers: [1, 2, 3, 4, 5]) == 57
// sumOfSquaredNumbers(numbers: [1, -2, 3, -4, 5]) == 35
func sumOfSquaredNumbers(numbers: [Int]) -> Int {
    var sum = 0
    for _, n in numbers {
        sum += n * n
    }
    return sum
}

// Given an array of integers, return

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

func sum(numbers: [Int]) -> Int {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return sum
}

func average(numbers: [Int]) -> Double {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return Double(sum) / Double(numbers.Count)
}

func median(numbers: [Int]) -> Double {
    var sortedNumbers: [Int] = numbers.SortedArray(ascending: true)
    var middleIndex: Int = sortedNumbers.Count / 2
    if sortedNumbers.Count % 2 == 0 {
        return Double(sortedNumbers[middleIndex] + sortedNumbers[middleIndex - 1]) / 2
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestLength = string.Length
            longestString = string
        }
    }
    return longestString
}

// In array of numbers, return the sum of all the numbers. Return 0 in case of an empty array.
// sum([1, 2, 3]) == 6
// sum([1, -2, 3]) == 2
// sum([]) == 0
func sum(numbers: [Int]) -> Int {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return sum
}

// In array of numbers, return the average of all the numbers. Return 0 in case of an empty array.
// average([1, 2, 3]) == 2
// average([1, -2, 3]) == 0
// average([]) == 0
func average(numbers: [Int]) -> Double {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return Double(sum) / Double(numbers.Count)
}

// In array of numbers, return the median of all the numbers. Return 0 in case of an empty array.
// median([1, 2, 3]) == 2
// median([1, -2, 3]) == 0
// median([]) == 0
func median(numbers: [Int]) -> Double {
    var sortedNumbers: [Int] = numbers.SortedArray(ascending: true)
    var middleIndex: Int = sortedNumbers.Count / 2
    if sortedNumbers.Count % 2 == 0 {
        return Double(sortedNumbers[middleIndex] + sortedNumbers[middleIndex - 1]) / 2
    } else {
        return Double(sortedNumbers[middleIndex])
    }
}

// In array of numbers, return the mode of all the numbers. Return 0 in case of an empty array.
// mode([1, 2, 3]) == 1
// mode([1, -2, 3]) == 1
// mode([1, 1, 1, 2, 3]) == 1
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2
// mode([1, 2, 3, 2, 2, 2, 3, 3, 3]) == 2

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestString = string
            longestLength = string.Length
        }
    }
    return longestString
}

func smallest(numbers: [Int]) -> Int? {
    var smallestNumber: Int? = nil
    var smallestValue: Int = Int.Max
    for _, number in numbers {
        if number < smallestValue {
            smallestNumber = number
            smallestValue = number
        }
    }
    return smallestNumber
}

func largest(numbers: [Int]) -> Int? {
    var largestNumber: Int? = nil
    var largestValue: Int = Int.Min
    for _, number in numbers {
        if number > largestValue {
            largestNumber = number
            largestValue = number
        }
    }
    return largestNumber
}

func sum(numbers: [Int]) -> Int {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return sum
}

func average(numbers: [Int]) -> Double {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return Double(sum) / Double(numbers.Count)
}

func median(numbers: [Int]) -> Int {
    var sortedNumbers: [Int] = numbers.Sorted()
    var middleIndex: Int = Int(sortedNumbers.Count / 2)
    if sortedNumbers.Count % 2 == 0 {
        return sortedNumbers[middleIndex]
    } else {
        return (sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestString = string
            longestLength = string.Length
        }
    }
    return longestString
}

// Out of array of numbers, return the smallest one. Return the first one in case of multiple
// numbers of the same value. Return nil in case the input array is empty.
// smallest(numbers: [] as [Int]) == nil
// smallest(numbers: [1, 2, 3]) == 1
// smallest(numbers: [3, 2, 1]) == 1
func smallest(numbers: [Int]) -> Int? {
    var smallestNumber: Int? = nil
    var smallestValue: Int = Int.Max
    for _, number in numbers {
        if number < smallestValue {
            smallestNumber = number
            smallestValue = number
        }
    }
    return smallestNumber
}

// Out of array of numbers, return the largest one. Return the first one in case of multiple
// numbers of the same value. Return nil in case the input array is empty.
// largest(numbers: [] as [Int]) == nil
// largest(numbers: [1, 2, 3]) == 3
// largest(numbers: [3, 2, 1]) == 3
func largest(numbers: [Int]) -> Int? {
    var largestNumber: Int? = nil
    var largestValue: Int = Int.Min
    for _, number in numbers {
        if number > largestValue {
            largestNumber = number
            largestValue = number
        }
    }
    return largestNumber
}

// Out of array of numbers, return the sum of all numbers. Return 0 in case the input array is
// empty.
// sum(numbers: [] as [Int]) == 0
// sum(numbers: [1, 2, 3]) == 6
// sum(numbers: [3, 2, 1]) == 6
func sum(numbers: [Int]) -> Int {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return sum
}

// Out of array of numbers, return the average of all numbers. Return 0 in case the input array is
// empty.
// average(numbers: [] as [Int]) == 0
// average(numbers: [1, 2, 3]) == 2
// average(numbers: [3, 2, 1]) == 2
func average(numbers: [Int]) -> Double {
    var sum: Int = 0
    for _, number in numbers {
        sum += number
    }
    return Double(sum) / Double(numbers.Count)
}

// Out of array of numbers, return the median of all numbers. Return 0 in case the input array is
// empty.
// median(numbers: [] as [Int]) == 0
// median(numbers: [1, 2, 3]) == 2
// median(numbers: [3, 2, 1]) == 2
func median(numbers: [Int]) -> Int {
    var sortedNumbers: [Int] = numbers.Sorted()
    var middleIndex: Int = Int(sortedNumbers.Count / 2)
    if sortedNumbers.Count % 2 == 0 {
        return sortedNumbers[middleIndex]
    } else {
        return (sortedNumbers[middleIndex - 1] + sortedNumbers[middleIndex]) / 2
    }
}

// Out of array of numbers, return the mode of all numbers. Return 0 in case the input array is
// empty.
// mode(numbers: [] as [Int]) == 0
// mode(numbers: [1, 2, 3]) == 1
// mode(numbers: [3, 2, 1]) == 1
func mode(numbers: [Int]) -> Int {
    var counts: [Int] = [Int]([])
    for _, number in numbers {
        var count: Int = 0
        for _, n in numbers {
            if n == number {
                count += 1
            }
        }
        counts.Append(count)
    }
    var maxCount: Int = 0
    var maxIndex: Int = 0
    for index, count in counts {
        if count > maxCount {
            maxCount = count
            

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestString = string
            longestLength = string.Length
        }
    }
    return longestString
}

func split(numbers: [Int], chunkSize: Int) [[Int]] {
    var result: [[Int]] = [[Int]]()
    var chunk: [Int] = [Int]()
    var i: Int = 0
    for _, number in numbers {
        if i % chunkSize == 0 {
            result.append(chunk)
            chunk = [Int]()
        }
        chunk.append(number)
        i += 1
    }
    result.append(chunk)
    return result
}

func evens(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 == 0 {
            result.append(number)
        }
    }
    return result
}

func odds(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 != 0 {
            result.append(number)
        }
    }
    return result
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestLength: Int = 0
    for _, string in strings {
        if string.Length > longestLength {
            longestString = string
            longestLength = string.Length
        }
    }
    return longestString
}

// In: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Out: [1, 2, 3, 4, 5]
// split(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], chunkSize: 5) == [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
func split(numbers: [Int], chunkSize: Int) [[Int]] {
    var result: [[Int]] = [[Int]]()
    var chunk: [Int] = [Int]()
    var i: Int = 0
    for _, number in numbers {
        if i % chunkSize == 0 {
            result.append(chunk)
            chunk = [Int]()
        }
        chunk.append(number)
        i += 1
    }
    result.append(chunk)
    return result
}

// In: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Out: [2, 4, 6, 8, 10]
// evens(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == [2, 4, 6, 8, 10]
func evens(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 == 0 {
            result.append(number)
        }
    }
    return result
}

// In: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Out: [1, 3, 5, 7, 9]
// odds(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == [1, 3, 5, 7, 9]
func odds(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 != 0 {
            result.append(number)
        }
    }
    return result
}

// In: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Out: [1, 3, 5, 7, 9]
// odds(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == [1, 3, 5, 7, 9]
func odds(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 != 0 {
            result.append(number)
        }
    }
    return result
}

// In: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
// Out: [2, 4, 6, 8, 10]
// evens(numbers: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) == [2, 4, 6, 8, 10]
func evens(numbers: [Int]) -> [Int] {
    var result: [Int] = [Int]()
    for _, number in numbers {
        if number % 2 == 0 {
            result.append(number)
        }
    }
    return result
}

// In: [1, 2, 3, 

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  
  return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  
  return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else {
    return nil
  }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  var longest = strings[0]
  for string in strings {
    if string.count > longest.count {
      longest = string
    }
  }
  return longest
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}
```

func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
  guard !strings.isEmpty else { return nil }
  
  var longestString = strings[0]
  
  for string in strings {
    if string.count > longestString.count {
      longestString = string
    }
  }
  
  return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }

    var longestString = strings[0]
    var maxLength = strings[0].count

    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }

    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }

    var longestString = strings[0]
    var maxLength = strings[0].count

    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    var maxLength = longestString.count

    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }

    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]
    var maxLength = longestString.count

    for string in strings {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longest = strings[0]
    for string in strings[1..<strings.count] {
        if string.count > longest.count {
            longest = string
        }
    }

    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longest = strings[0]
    for string in strings[1..<strings.count] {
        if string.count > longest.count {
            longest = string
        }
    }

    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings[0]

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    var maxLength = longestString.count
    
    for string in strings[1...] {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    var maxLength = longestString.count
    
    for string in strings[1...] {
        if string.count > maxLength {
            longestString = string
            maxLength = string.count
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings[1..<strings.count] {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longest = strings[0]
    
    for string in strings[1..<strings.count] {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }

    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }

    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }

    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }

    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}

<start_of_turn>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<end_of_turn>
<start_of_turn>model
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longest = strings[0]
    
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    var longestString = strings.first
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    var longestString = strings.first
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings.first
    var longestLength = longestString?.count ?? 0

    for string in strings {
        let length = string.count
        if length > longestLength {
            longestString = string
            longestLength = length
        } else if length == longestLength {
            return string
        }
    }

    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    var longestString = strings.first
    var longestLength = longestString?.count ?? 0

    for string in strings {
        let length = string.count
        if length > longestLength {
            longestString = string
            longestLength = length
        } else if length == longestLength {
            return string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    let longestString = strings.max(by: { $0.count < $1.count })
    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }

    let longestString = strings.max(by: { $0.count < $1.count })
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted(by: { $0.count > $1.count }).first
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString
    var longestLength = firstString.count

    for string in strings {
        if string.count > longestLength {
            longestString = string
            longestLength = string.count
        }
    }

    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString
    var longestLength = firstString.count

    for string in strings {
        if string.count > longestLength {
            longestString = string
            longestLength = string.count
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else { return nil }
    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString

    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard let firstString = strings.first else {
        return nil
    }

    var longestString = firstString
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

[INST] Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc" [/INST] ```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest!.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }

    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString: String?
    
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString: String?
    var maxLength = 0

    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }

    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }

    var longestString: String?
    var maxLength = 0

    for string in strings {
        if string.count > maxLength {
            maxLength = string.count
            longestString = string
        }
    }

    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.sorted { $0.count > $1.count }.first
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard let first = strings.first else {
        return nil
    }
    
    var longest = first
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

You are an AI programming assistant, utilizing the Deepseek Coder model, developed by Deepseek Company, and you only answer questions related to computer science. For politically sensitive questions, security and privacy issues, and other non-computer science questions, you will refuse to answer
### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if string.count > longestString?.count?? 0 {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if string.count > longestString?.count?? 0 {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}
```

func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard let longest = strings.max(by: { $0.count < $1.count }) else { return nil }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength = 0
    for string in strings {
        if string.count > longestStringLength {
            longestString = string
            longestStringLength = string.count
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength = 0
    for string in strings {
        if string.count > longestStringLength {
            longestString = string
            longestStringLength = string.count
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
    return nil
}
```

func longest(strings: [String]) -> String? {
    // Your code here
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // Your code here
}
```

func longest(strings: [String]) -> String? {
    var longest = strings.first
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest = strings.first
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    var longest = strings.first
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest = strings.first
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    return nil
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return nil
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longest = strings[0]
    for string in strings {
        if string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    guard strings.count > 0 else {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard strings.count > 0 else {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    return strings.max(by: { $0.count < $1.count })
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    var longestLength = 0
    for string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    var longestLength = 0
    for string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    // TODO: Implement this function
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    // TODO: Implement this function
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    var longestLength = 0
    for string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    var longestLength = 0
    for string in strings {
        if string.length > longestLength {
            longestString = string
            longestLength = string.length
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if string.count > longest?.count?? 0 {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest = nil
    for string in strings {
        if longest == nil || string.count > longest.count {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longest: String?
    for string in strings {
        if longest == nil || string.length > longest.length {
            longest = string
        }
    }
    return longest
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"<|im_end|>
<|im_start|>assistant
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength = 0
    for string in strings {
        if string.count > longestStringLength {
            longestString = string
            longestStringLength = string.count
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    var longestStringLength = 0
    for string in strings {
        if string.count > longestStringLength {
            longestString = string
            longestStringLength = string.count
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString.isEmpty ? nil : longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString = ""
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString.isEmpty ? nil : longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

func shortest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.min(by: { $0.count < $1.count })
}

func vowelCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        vowelCount(string: $0) < vowelCount(string: $1)
    })
}

func vowelCount(string: String) -> Int {
    let vowels = "aeiou"
    return string.reduce(0) { $0 + (vowels.contains($1) ? 1 : 0) }
}

func consonantCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        consonantCount(string: $0) < consonantCount(string: $1)
    })
}

func consonantCount(string: String) -> Int {
    let consonants = "bcdfghjklmnpqrstvwxyz"
    return string.reduce(0) { $0 + (consonants.contains($1) ? 1 : 0) }
}

func punctuationCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        punctuationCount(string: $0) < punctuationCount(string: $1)
    })
}

func punctuationCount(string: String) -> Int {
    let punctuation = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
    return string.reduce(0) { $0 + (punctuation.contains($1) ? 1 : 0) }
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: { $0.count < $1.count })
}

// Out of array of strings, return the shortest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// shortest(strings: [] as [String]) == nil
// shortest(strings: ["a", "b", "c"]) == "c"
// shortest(strings: ["a", "bb", "ccc"]) == "a"
func shortest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.min(by: { $0.count < $1.count })
}

// Out of array of strings, return the one that contains the most vowels. Return the first one
// in case of multiple strings with the same number of vowels. Return nil in case the input
// array is empty.
// vowelCount(strings: [] as [String]) == nil
// vowelCount(strings: ["a", "b", "c"]) == "a"
// vowelCount(strings: ["a", "bb", "ccc"]) == "ccc"
func vowelCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        vowelCount(string: $0) < vowelCount(string: $1)
    })
}

func vowelCount(string: String) -> Int {
    let vowels = "aeiou"
    return string.reduce(0) { $0 + (vowels.contains($1) ? 1 : 0) }
}

// Out of array of strings, return the one that contains the most consonants. Return the first
// one in case of multiple strings with the same number of consonants. Return nil in case the
// input array is empty.
// consonantCount(strings: [] as [String]) == nil
// consonantCount(strings: ["a", "b", "c"]) == "b"
// consonantCount(strings: ["a", "bb", "ccc"]) == "bb"
func consonantCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        consonantCount(string: $0) < consonantCount(string: $1)
    })
}

func consonantCount(string: String) -> Int {
    let consonants = "bcdfghjklmnpqrstvwxyz"
    return string.reduce(0) { $0 + (consonants.contains($1) ? 1 : 0) }
}

// Out of array of strings, return the one that contains the most punctuation. Return the first
// one in case of multiple strings with the same number of punctuation. Return nil in case the
// input array is empty.
// punctuationCount(strings: [] as [String]) == nil
// punctuationCount(strings: ["a", "b", "c"]) == "b"
// punctuationCount(strings: ["a", "bb", "ccc"]) == "bb"
func punctuationCount(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    return strings.max(by: {
        punctuationCount(string: $0) < punctuationCount(string: $1)
    })
}

func punctuationCount(string: String) -> Int {
    let punctuation = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~"
    return string.reduce(0) { $0 + (punctuation.contains($1) ? 1 : 0) }
}

// Out of array of strings, return the one that contains the most digits. Return the first one
// in case of multiple strings with the same number of digits. Return nil in case the input
// array is empty.
// digitCount(strings: [] as [String]) == nil
// digitCount(strings: ["a", "b", "c"]) == "b"
// digitCount(strings: ["a", "bb", "ccc"]) == "bb"
func digitCount(strings: [String]) -> String? {
    guard !strings

func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

```swift
// Out of array of strings, return the longest one. Return the first one in case of multiple
// strings of the same length. Return nil in case the input array is empty.
// longest(strings: [] as [String]) == nil
// longest(strings: ["a", "b", "c"]) == "a"
// longest(strings: ["a", "bb", "ccc"]) == "ccc"
func longest(strings: [String]) -> String? {
    if strings.count == 0 {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else {
        return nil
    }
    
    var longestString = strings[0]
    
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String?
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if let longest = longestString, string.count <= longest.count {
            continue
        }
        longestString = string
    }
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if let longest = longestString, string.count <= longest.count {
            continue
        }
        longestString = string
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}

system
You are a helpful assistant.
user
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
assistant
```swift
func longest(strings: [String]) -> String? {
    guard !strings.isEmpty else { return nil }
    
    var longestString: String? = nil
    for string in strings {
        if longestString == nil || string.count > longestString!.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $1.count > $0.count ? $1 : $0 }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.reduce(strings[0]) { $0.count > $1.count ? $0 : $1 }
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

### Instruction:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"
### Response:
```swift
func longest(strings: [String]) -> String? { 
    guard !strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    if strings.isEmpty {
        return nil
    }
    
    var longestString = strings[0]
    for string in strings {
        if string.count > longestString.count {
            longestString = string
        }
    }
    
    return longestString
}
```

func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}

Question:
Write code in Swift programming language. Don't include usage examples or tests.
Out of array of strings, return the longest one. Return the first one in case of multiple
strings of the same length. Return nil in case the input array is empty.
longest(strings: [] as [String]) == nil
longest(strings: ["a", "b", "c"]) == "a"
longest(strings: ["a", "bb", "ccc"]) == "ccc"

Answer:
```swift
func longest(strings: [String]) -> String? {
    guard!strings.isEmpty else { return nil }
    return strings.max { $0.count < $1.count }
}
```